Core Java Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Core Java Interview Questions

Questions Answers Views Company eMail

my method "abc" return array of interface "xyz" and "pqr" is abstract class implements abc and class "jkl" extends pqr My problem 1) when i call abc it retrun array xyz how can i do this hint xyz refer_xyz = new jkl(); but i can't create array. 2)I want to access method of jkl using reference of xyz??

1 3842

why interaction with server using javascript is difficult

1 3775

StringBuilder s = new StringBuilder("Hello Mom");s.append(",I mean,Mother"); Response.Write(s.ToString()); String s = "Hello Mom"; s+ = ",I mean Mom"; Response.Write(s); Which is faster ? which uses the most memory?

HCL,

6 8764

I have one Shopping cart application, i that i have selected some items, while clicking submit button by mistake i have clicked twice or trice, that time items are selected twice or trice. Actually i want only one copy of items but its selected twice or trice. So how can we avoid this problem?

Honeywell,

2 6705

How Vector class is synchronized,How to build user defined class as synchronized?

2028

What is difference between abstract class & final class

7 26784

Hai all I want to print given array in reverse order Ex: int a[]={1,2,3,4,5};display this array in reverse order.

4 5916

what is the output ? Math.floor(-2.1) a)2 b)-2 c)-3.0 d)0

Accenture,

4 13743

How to find the size of an array a)array.length() b)array.length c)array.size() d)array.size

Accenture,

6 10790

what is the Yield() method used in threads?

Accenture,

4 8413

System.out.println(101/14) what is the output? a)6 b)14 c)7.14 d)0

Accenture,

8 10445

when a servlet sends request for first time it uses the follwing methods a)init b)doget() c)dopost() d)service

Accenture,

4 7375

What is Hash Code in Java?

Cognizant,

6 15748

What are uses of Hash Code?

Cognizant,

2 7354

I have 100 records in a table with two rows. I need to display 10 records per page like Google Search. I need only the Logic(Pagination) in Pure Java. No JSP and all..Thanks in Advance...

Cybernet,

2 7907

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Un-Answered Questions { Core Java }

Explain the hierarchy of java exception classes?

1028

What is the maximum length of a url?

895

Does collectionutils isempty check for null?

1377

Tell me how many ways are there to initialise an integer with a constant.

1067

What is a class variable?

992

Does java arraylist maintain insertion order?

947

What is a default method?

997

What is string args [] in java?

984

What is flush () in java?

967

Why is java called the platform independent programming language?

961

I want to persist data of objects for later use. What’s the best approach to do so?

881

Can you access non static variable in static context?

994

What is meant by data hiding/encapsulation?

1055

Can I use % with real numbers?

971

What are the classes of java?

931

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